Oops I Did it Again - Another Lot of Computers Needing Repair

Recently I was browsing the retro computer forums and a for sale ad came up in my city.  A fellow Macintosh computer enthusiast had purchased a lot of Macintosh machines to restore and the project sat for a long time.  He decided to shift the project along to someone else.  The listing had a single photo and some text, the photo showed seven machines and one box full of peripherals.  The text described another box of peripherals not shown but included in the sale.  The price was low enough that I could purchase the entire lot and if my repair attempts failed I'd still have gotten some much needed peripherals for my collection.  But as readers of my blog will know, I really enjoy the repair process and so I was hoping that I'd be able to repair much of this lot and sell it on, since these were all machines that I had, and I even had some parts machines of this type.

When I got the lot home this is what I had...

The lot consisted of; 2 512K Macs, 3 Macintosh Plus machines, a Mac SE and a Mac Classic II along with the peripherals, an external 400K floppy, an HD20, and a couple of different keyboards and even a couple of random vintage PC parts.  As usual I began the intake process with some light cleaning.  It was no surprise but the equipment was quite dusty, including inside of the machines, so I think it was likely these machines spent quite a few years in a garage or basement.

On my initial checks (triage), both of the 512K macs booted to a ?.  I'm quite certain the floppy drives will need lubrication and maintenance so I've set those machines aside for now.

For the Mac Plus machines, 2 of the 3 booted right up to the ?.  The third machine was booting, but showing some odd video corruption of a kind I had not seen before.  On further inspection that machine had a 68030 accelerator board inside of it.  It's possible this accelerator board is damaged, but I need to do some research to figure that out, so I've set the accelerator board aside for now.

The Mac SE booted up to a ?.  This was a project I wanted to work on in the short term because I have a couple of other Mac SEs including one mostly good machine with bad Floppy Drives and one parts machine.  I was hoping to get two working Mac SEs out of these three, but more on that later.

The Mac Classic II made a normal good chime on boot up, but the video did not come up.  These machines from the early 1990s are often damaged for two reasons, the first is an exploding clock battery, and the second is the "Capacitor Plague" where Apple unknowingly used sub-standard electrolytic capacitors that slowly leak out onto the circuit board.  Both of these problems can ruin Mac Classic and Mac Classic II machines and so all of these machines should be serviced ASAP.  Fortunately for me, the clock battery had not leaked, so I removed it.  The capacitors had been leaking so I removed them immediately and got to work cleaning the board to prepare it for a recap.

I worked on the Mac SE and the Classic II at the same time.  For me, a big part of the experience with the original style Mac computers is using the Floppy Disk drives.  Servicing them can be tedious and error prone, but there are some great tutorial videos out there, and once you've done each type of drive a couple of times it starts to come easier.  But it can be tedious when there are many drives to service.  I try to keep one or two of each type of drive in my stock because often drives will require spare parts not just lubrication so I got the drives out of the Classic II and the Mac SE along with some of my spares and got started...

Having these drives ready allowed me to start the repairs in earnest.  As I've mentioned, I had a couple of other Mac SE machines and I checked on those floppy drives that were not working, and they had already been serviced.  It turns out that the reason they weren't booting was because I had some bad boot floppies, so that was one mystery solved.

The Mac SE from this lot had badly yellowed in the sun, but my parts machine was still a great looking platinum case, so I did a case swap on the Mac SE and got a lovely looking fully running machine...

I don't need 3 Macintosh SEs so I currently have this machine listed for sale locally here in the Minneapolis / St. Paul area.

The Mac Classic II repair took a bit longer because I had to order capacitors and wait for those to arrive for the recap.  Also it took a while to clean the logic board of this machine using both water and IPA and multiple manual rinse cycles.  I also had a parts machine for this repair, a Classic machine that I'd previously recapped but that machine never worked quite right after the recap it would boot and run just fine but the external SCSI and FDD ports weren't quite right.  It's possible that further board level work could bring this machine back to full function, but I was able to use the Classic to help troubleshoot the Classic II.

It turns out that not only did the Classic II need a recap on the logic board but the analog board was bad as well.  I did another swap on the analog boards and CRT boards to get a good setup into the Classic II case.  After swapping the Analog board the Classic II came back to life, and with the recap and cleaning, I'm hopeful that this machine will have a long and happy future.  Classics and Classic II machines are not my favorite from this time period, so this is another machine that is for sale here in the Minneapolis / St. Paul area...

I'm still actively working on fixing up the Macintosh Plus machines.  I have all three of them running again because I was able to borrow parts off another parts machine that I had, so the next step is servicing another set of Floppy Disk drives, the earlier 800K drives that came in the Mac Plus and Mac SE...

Since I already have a couple of nice Mac Plus machines I plan to offer these machines for sale when the Floppy Servicing is complete.  Hopefully I can complete the Plus repairs this weekend and get back to the other projects I was working on when this lot came up.  It's been alot of fun doing these repairs but I'll also be glad to move back to my "regularly scheduled programing" of Retro Computer projects.

Do you have memories of using these machine?  Let me know if you have stories you'd like to share in the comments, or my email address is in my profile.  Thanks for following along with this repair story.

The Original Slide Rule Replacement - Hewlett Packard Handheld Scientific Calculator

As I have pointed out in a previous post, I am a calculator collector.  As I was doing research about HP Calculators in order to replace the one used during my college years, I learned of the original handheld scientific calculator.  This was invented by HP in the early 70s.  At first the machine didn't even have a model name, it was just the HP Handheld Calculator, but later it was labelled as the HP 35 since it had 35 keys on it.

As of this writing in early 2025 prices for the original HP 35 are rising with good working examples going for several hundred dollars on eBay.  These are much more repairable than modern calculators and there is at least one detailed tutorial video showing the process to take them apart and clean them.  The repairability and information online made me feel comfortable enough to purchase a non-working unit on eBay and attempt a repair myself, but things are often more complicated than initially expected.

The unit arrived and I was able to take it apart as shown in the video.  There were signs that this one had already been taken apart, which was disappointing since that was not shown in the eBay listing.  I should have asked for pictures of the back.  Cleaning the contacts did not resolve the dead keys on this calculator as it did in the YouTube video so it turns out that this calculator had something wrong with the electronics on the main circuit board.  I reflowed the solder joints and poked around on the main board a bit, it isn't very complicated, but I'm guessing one of the custom logic ICs is damaged, so this project went on hold for a few weeks.

Shortly after I got an email from one of my saved searches on eBay.  It was the cheapest HP35 on eBay in. quite a while.  It was a loose calculator without a Power Supply.  I talked to the seller and he had no way to power it up, so it was a gamble, but he also showed the back of the unit and this one had not been opened, so I took the chance and purchased it.

The second calculator was in really rough shape.  When I got it on the workbench it had battery corrosion on the inside of the battery compartment and it wouldn't power up.  I started disassembly, cleaning as I went.  It was obvious that corrosion had gotten inside and affected the power circuits under the battery compartment, however, the design was modular and that was not a part of the main logic board that was bad on the other calculator, so I was still hopeful.

When I swapped the older logic board onto the newer HP35 it fired right up and worked!  I was very happy to have a working calculator after buying two broken ones.  As soon as I got one working I checked for the 2.02 bug.  The working Logic Board is from the first year, 1972, but it does not have the bug, which is OK with me since it would have looked out of place in the newer case with the H P 35 logo on the front.

I also rebuilt the battery pack with 3 NiCd AA cells and it looks quite nice running without being plugged in...

So now that I have the first ever scientific calculator, the HP 35, and my favorite calculator, the HP48G that got me through college.  These are the bookends for my collection and should not really need any more calculators in the collection.  For now.

Another Beige Alpha Joins the Fleet - Compaq Professional Workstation XP1000

In the middle of last year an interesting workstation computer came up for sale on Facebook Marketplace here in my area.  The Compaq Professional Workstation XP1000 is an Alpha based workstation from just after Compaq purchased Digital Equipment Corporation.  The Facebook Markeplace ad stated that it was stopping on a boot screen and that it might not be working, but the price was low enough that I thought it was worth the risk of not being able to repair it.

Once I got the system home I was able to verify that the system was in the condition described and then started to read what I could find about this computer.  I soon discovered that the motherboard had a password installed on it.  In the PC world we would call this a BIOS password, but for an Alpha machine like this, it's the SRM console password.  The SRM console uses a command line but with it locked out even the help command was generating an error "Console is secure.  Please login.".  Because PCs have a jumper to reset this I was quite hopeful that it would just be a matter of time till I figured out how to reset that password but after not finding much documentation online I decided to ask for help on the Vintage Computer Federation Forums.

As usual there were several people who were a big help there, including one gentleman that uploaded some documentation to the thread that I had not been able to find online anywhere else.  Sadly, though, we did NOT discover a backdoor designed by Compaq to reset the console password.  Although I could not find an explicit statement for this motherboard I did learn that were other machines designed by Compaq that did not contain a back door, if the password is lost, the main logic board containing the firmware must be replaced.  So I decided to put the project on hold and keep the machine.  I setup a saved search on eBay since you never know what will pop up there and didn't think much about this project in the second half of last year.

At the end of last year I gave quite a bit of thought to my Vintage Computing hobby.  I purged alot of my project machines, selling, donating to Free Geek, or recycling responsibly.  I also went through my wish lists and eBay saved searches and purged items that were no longer of interest and I discovered that I had setup the wrong search, adding an extra zero.  When I fixed the saved search I was shocked to learn that there was a logic board on eBay for sale!  I watched the item for a while and eventually made an offer that was accepted.

The board shipped from Israel so it took a while to get here but once it arrived I was able to pull my machine completely apart.  I used this as an opportunity to do some much needed dusting inside the case of this machine.  It was a huge relief when the system started back up after re-assembly and an even bigger relief when I was able to use the SRM console and issue commands to boot an Operating System off an Installation Disk!

Once I could start to explore, I learned that this was one of the newer XP1000 machines.  This machine can run the VMS operating systems and Unix like systems, but not Windows NT.  The older, slower machines could boot NT, but I already have one Alpha machine setup that way.  I know at least one DEC hardware enthusiast  who will be glad to see the machine running DEC software and not Microsoft software.

I had some old media for OpenVMS which I had burned while I was a part of the Community Licensing program, but that program has ended now.  I was able to install OpenVMS 8 on the hardware, but without licenses it's not very interesting or useful.  After searching on the Internet and reading for a bit, I learned that the archived version of Tru64 Unix on WinWorld has keys with the archive, so I gave that a try, and it worked well.

Configuring networking was a bit of a challenge, but I ended up getting that working with a Static IP and now the computer can read articles on FrogFind.com and 68k.news just fine.  I'm quite happy with how the machine turned out...

I was disappointed that I couldn't load older software on here.  I have been looking for some VAX hardware since that is what we used back in College, I remember the Motif Window Manager and that was such an interesting look and feel, but I didn't know that Motif was the precursor to the Common Desktop Environment (CDE).  Because of multiple vendors working together on this more open code base this Compaq (Digital Equipment) machine will join several others CDE machines that I have including IBM AIX, Sun Solaris, and SGI Irix.

I am not a calculator collector, I am not a calculator collector.

I am not a calculator collector.  I have to keep saying this to myself because I don't need another genre of items to collect, but I'm quite tempted by this since it is adjacent to retro computing.  I've managed to avoid printers (mostly), typewriters completely, and vintage test equipment, among many other interesting items that I would collect if time money and storage space were not limited.

So I have a few calculators.  I purchased a Radio Shack Pocket Computer 4 off Facebook Marketplace in 2020...

And since then I've been picking up interesting, older calculators from the 70s and 80s at Garage Sales and Thrift Shops when I can find them including a couple of hand held Casio units.  My parents had a Casio on their desk, it had a mesmerizing Nixie tube display and so although it was "portable / battery powered" it stayed plugged in and on the desk.  The Calculator Wars of the 70s were historically significant to the development of home computing as they occurred right before the home computer revolution and included many of the same companies.  Calculators were the "killer app" of Microprocessors before the home computer revolution began, but this is well covered elsewhere.

My personal calculator history started with my first graphing calculator, a TI-81.  My parents bought this for me while I was in high school and I spent quite a bit of time puttering with it and even wrote some simple programs to run on it.  I was recently able to reacquire a TI-81 from Free Geek Twin Cities and add that to my calculator not-a-collection.

My favorite calculator is the HP48G which got me through engineering school.  Back in the day we didn't have laptop computers for every student so pretty much everyone had an HP 48 of some sort.  It was hard to learn how to use it, but once I'd gotten the hang of it I can always come back to an RPN calculator, just like riding a bicycle, you never really forget how.  There's a review video from Calculator Culture on YouTube that I'd recommend, it has helped me understand why this calculator is so unique.

I wore out my initial 48G calculator.  I had tried to repair it at one point, but it was not designed for service and I ended up breaking mine.  I missed having it enough that about ten years ago I had purchased an HP50G calculator hoping that it would replace my worn out calculator, but I didn't like using it as much.  Another Calculator Culture review video explains this calculator well.  I ended up selling my HP50G as it didn't really match my expectations and was different enough from the 48 that is just didn't feel the same.

So after watching a few videos from HPcalc.org's recent conference and the Calculator Culture videos I realized that the best way to "Scratch the Itch" so to speak would be to just go ahead and buy an original HP48G.  With my new knowledge about the hardware revisions and the typical problems, I was hoping I could find a nice one on eBay at a reasonable price, and after waiting and shopping for a couple of weeks, I was able to find this lovely unit here...

I've paired it with the original manual set that I'd kept all these years.  I'm glad I kept the manual since there's alot I've forgotten about how to use the machine (the manual is hundreds of pages long).  As described in the review video above the LCD screen isn't great, the contrast is poor, although not being backlit means that the battery life is quite good.  The keyboard is amazing, the keys are clicky, very tactile and enjoyable to use.

I've enjoyed having this machine back at my desk, and I'm getting back into the habit of using it.  During my research I've also found a much more modern iOS app that emulates the 48.  I've used about a half dozen of these over the years since getting my first Smart Phone and this one is the most useful and stable, it's called iHP48 and it is much better than other iOS Apps that emulate HP 48 which I have used before.  This is the main calculator app on my phone now and I use it almost daily.

Doing the research about HP 48 and being exposed to other calculator collectors has helped me learn about the history and development of the handheld scientific calculator.  I've become aware of the first Handheld Scientific Calculator, the HP 35 from 1972.  But this is a story for another day, so I will wrap up this bLog post by simply stating the obvious, I am a calculator collector.

My Newest, Oldest Apple II Plus (1979)

There were three very important home computers that came out in 1977, the Commodore PET, the Apple II and the Radio Shack TRS-80 Computers.  We retroactively call the Radio Shack the TRS-80 Model 1 but that is not how it was advertised at the time.  Also, the use of the term trinity to describe these three computers is something that appears to have begun in the mid 90s.

One of my goals in the Retro Computing hobby is to own all three of the original premade personal computers that didn't have to be built from kits like the Altair 8800.  So far I have been able to acquire; an Apple II Plus from 1979, a Commodore PET 4016 from 1980, and an original TRS-80 Model 1 computer.

Recently on a trip to Free Geek Twin Cities I was able to acquire another Apple II Plus machine and this turned out to be a machine from 1979.  This got me thinking again about wanting to get as close as possible to an original Apple II experience from 1977 and so I started doing research.  Tech Time Traveller has a really helpful video on this topic here.  He also painnstakingly built up this list of machines have have sold on eBay, since eBay doesn't keep pricing information and old listings around on their site very long  Thanks Tech Time Traveller!  Now that I know an original Apple II from eBay is probably more than I want to spend right now, what are my options?

Going back to the machine from  Free Geek, I learned that the board in my "newest" Apple II Plus is a "Revision 4" logic board.  This is from the period in 1979 was when Apple was making both the II and the II Plus at the same time, and often with the same logic board and only different ROMs and different RAM amounts.

At the same time as this was going on a listing came up on eBay for a computer that was listed as an original Apple II machine, but after inspecting it it seems likely that this machine had been upgraded to II Plus, which I later confirmed was the consensus in one of the Apple II Facebook groups.  I'm still considering the option of building an "Original Apple II" by getting bits and pieces and putting them together, but I think I'd rather hold out and wait till one comes along that is more complete locally, or with a backstory that I can learn about.

In the meantime, I learned about the Apple II ROM card, which was a period correct accessory card from 1979 that folks bought when they were upgrading their Apple IIs to Apple II Plus which allowed them to put the old ROMs onto an expansion board and switch them in at will from a switch on the back of the computer.  I used to have a modern card that did this, but ironically that card failed, so I set out to find a vintage card that still had the correct ROMs on it (Many, perhaps most of the ones on eBay have been stripped).  This article on the VCFed forums explains which ROMs where the period correct ones for an original Apple II (With Woz's Integer basic, and without Applesoft Basic).  I was able to find and acquire one of these period correct cards with the full ROM set, and it works great...

So, as of this writing, my Apple II Plus behaves in exactly the same way as the original machine, so I am now able to explore software from that era.  A good win for a reasonable price with parts that are still relatively inexpensive.